/*
** 2405.c
** 
** Made by (seakage2h)
** Login   <seakage2h@seakage2h-ubuntu>
** 
** Started on  Sun Oct 12 12:47:08 2008 seakage2h
** Last update Sun May 12 01:17:25 2002 Speed Blue
*/

/* #include "2405.h" */
#include <stdio.h>
#include <math.h>
#define pi 3.141592654

int main()
{
     int D, V;

     while(scanf("%d%d", &D, &V)){
	  if (D + V == 0) break;
	  printf("%.3lf\n", pow(D*D*D-6*V/pi, 0.3333333333));
     }

     return 0;
}

     
